Severe hypercalcemia in a patient treated for hypoparathyroidism with calcitriol.

Long term administration of calcitriol (1,25 - dihydroxyvitamin D) is recommended for the treatment of a number of endocrine and renal disorders associated with impaired calcium - phosphate metabolism. Administration of calcitriol, however, may give rise to undesirable side effects, such as hypercalcemia and hypercalciuria. The magnitude of hypercalcemia is the key consideration in determining the need for immediate and aggressive therapy. There are four main strategies for lowering serum calcium: decreasing intestinal calcium absorption; increasing urinary excretion; decreasing bone resorption; and removing excess calcium through dialysis. We report on an adolescent with thalassemia who developed severe hypercalcemia during regular clinical follow-up for hypoparathyroidism treatment with calcitriol and calcium. He was also receiving levothyroxine for primary hypothyroidism and iron chelation therapy with desferioxamine mesylate for the severe iron overload.